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Aim: At fine scales (<10 km in spatial resolution), only a few studies have evaluated the relationships between abiotic factors and the horizontal occurrence of vascular epiphytes. At fine scales, variation in abiotic variables can be attributed to topographic heterogeneity. For example, air humidity and wind speed are likely to vary along ridge–valley gradients, and differences in slope aspect cause variation in light intensity as well as temperature gradient along an elevation. We tested the hypothesis that the horizontal epiphyte occurrence at fine scales is influenced more by topographic gradients related to abiotic factors than by host tree size and species. We also assessed air humidity variation along the ridge–valley gradient at our study site as a way to explore its possible correlation with the epiphyte occurrence. Location: A coniferous/broadleaf evergreen mixed forest in a humid temperate zone of Kochi, southwest Japan. Methods: We surveyed epiphyte occurrence on 310 trees and recorded host tree size and species within a 52‐ha watershed with an elevational range of 378–777 m a.s.l. Epiphyte occurrence was modeled using three topographic variables (ridge–valley gradient, slope aspect differences and elevational gradient), host tree size and species. The effect sizes of each variable were then compared. Air humidity was measured on the valley bottom, slope and ridge throughout the year. Results: Epiphyte occurrence probability increased toward the valley bottom and on larger host trees; it also varied among host tree species. Slope aspect differences and elevational gradient were less effective. The ridge–valley gradient had a greater effect than host tree size on epiphyte occurrence. Air humidity was highest at the valley bottom and lowest on the ridge. Conclusions: Horizontal epiphyte occurrence was driven more by topographic gradient than by host tree size and species in a small watershed covered by a warm‐temperate broadleaf forest. This finding suggests the importance of forests at valley bottoms to support epiphyte occurrence. [ABSTRACT FROM AUTHOR]

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Purpose: There has been an increasing number of studies on species extinction because of global warming based on estimations of changes in species distributions. Life cycle impact assessment methods do not have a biodiversity damage factor for global warming that uses the extinction risk index. In this study, a method for determining the extinction risks of individual species per unit CO emission was proposed and test calculations of the extinction risks of 216 species of Japanese vascular plants were performed. We also examined the possibility of determining local and global extinction risk factors using this method. Methods: This method uses the Expected Increase in the Number of Extinction Species (EINES), which is defined as the inverse of the time to extinction, as the extinction risk index. Procedures for determining the extinction risks of individual species per unit CO emission (EINES/species/kg) are as follows. First, based on the base scenario of CO emission, a niche-based species distribution model is used to estimate species distribution areas in 2000 and 2100 and calculate the distribution area decrease over 100 years. The number of years before the zero distribution area is then determined by assuming that the decrease is constant. Extinction risk is defined as the inverse of this time. The final step is to determine the extinction risk at specific CO emissions in addition to the base emission scenario and divide the difference in the extinction risk by the additional amount of CO emissions. Results and discussion: The distribution areas of 216 species of Japanese vascular plants having southern distribution limits were estimated to decrease by 40-85% in 100 years. The accuracy of the estimation was sufficient according to the value of area under the curve (AUC). Considering climate models and migration conditions, the extinction risk per unit CO emission was estimated between −0.6 × 10 and 4.7 × 10 (EINES/species/kg). We converted the normalization values of the extinction risk of Japan for the 216 species to compare impact of land use changes and waste processing with that of global warming on the species. We found that global warming has smaller impact compared with land use changes and larger impact compared with waste processing. Conclusions: A method for estimating the extinction risks of species per unit CO emission was proposed, and it can be used to determine the local and global extinction risk factors of CO. [ABSTRACT FROM AUTHOR]